Moisture detecting base plate for an ostomy appliance and a system for determining moisture propagation in a base plate and/or a sensor assembly part

ABSTRACT

The disclosure relates to a system for determining and signalling moisture propagation in an adhesive material layer of a base plate and/or a sensor assembly part for an ostomy appliance. The disclosure further relates to aspects of a base plate and/or a sensor assembly part for an ostomy appliance and its use in such a system.

BACKGROUND

Stomal output often contains body fluids and visceral contents that areaggressive to both the skin of a user and to ostomy devices, these havea detrimental effect on the efficiency and integrity of the adhesivematerials that are applied to attach the ostomy device to the user'sskin surface. For users in general safe, reliable and efficient ostomydevices are evidently highly desirable.

However, a particularly major and persistent concern of a largepopulation of ostomists continues to be failure of the base plateadhesive attaching the ostomy appliance to the user's skin surface,because such failure almost inevitably leads to embarrassing andstigmatising leakage incidents. Such incidents in turn are known fromseveral user interviews to lead to a reduced quality-of-life feeling.Adhesive failure of the base plate adhesive can result from variousreasons. Most often, a leakage incident is caused by stomal outputentering between the proximal surface of the base plate and the user'sskin, e.g. due to less-than-optimal attachment of the base plate to theskin arising from e.g. uneven skin surface or skin folds. Thisundesirable progression of stomal output ‘underneath’ the adhesive leadsto deterioration and/or weakening of the adhesive material carrying theweight and providing the seal of the ostomy appliance. Often suchfailure happens surprisingly fast and is only detectable for the useronce the failure has already become so severe that leakage occurs,requiring immediate change of the ostomy appliance and possibly also ofthe user's clothes.

In other instances, the primary factor of adhesive failure is simply aquestion of how much time has elapsed since the base plate of the ostomyappliance was first applied to the user's skin surface. In addition tothe output from the stoma itself, the peristomal skin surfacecontinuously secretes some moisture (e.g. sweat). To mitigate this, mostoften adhesives of base plates for ostomy devices include hydrocolloidmaterials which are capable of absorbing high levels of moisture,thereby stabilizing the polymer matrix of the adhesive material andprolonging the lifetime (“wear time”) of the base plate. However,eventually the adhesion capability of the base plate no longer cansupport the force exerted on the base plate from the load of the outputcollecting bag, and the appliance must be replaced.

As there can be considerable differences in the severity and/or speed bywhich adhesive failure and potentially leakage occur, which differencesat least to some extent are correlated to various factors includingthose presented above, a mere indication that failure or leakage isimminent, or that it has already occurred, fails to represent a reliableand satisfactory solution to the problem of avoiding sudden embarrassingand stigmatising leakage incidents in ostomy appliances. In other words,the users of ostomy appliances could greatly benefit from an appliancesolution which provides them with better guidance and options regardinghow and—not least—how quickly to react to beginning failure or leakageof the adhesive of the base plate of the appliance. More generally,ostomists and health care professionals alike would welcome improvementsin ostomy devices to reduce or eliminate the occurrence of suddenleakage incidents.

SUMMARY

The present disclosure provides aspects of a base plate and/or a sensorassembly part for an ostomy appliance according to claim 1. Furtherdisclosed is a system for determining and signalling moisturepropagation in an adhesive material layer of a base plate and/or asensor assembly part for an ostomy appliance according to claim 32.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIG. 1 is an exploded, perspective view of one embodiment of a baseplate according to the first aspect of the disclosure.

FIG. 2 is a top view of one embodiment of the base plate of thedisclosure viewing down on a proximal surface of a backing layer.

FIG. 3 is a top view of one embodiment of a first sensor element of thebase plate.

FIG. 4 is a cross-sectional view of a portion of the base plateaccording to one embodiment.

FIG. 5 is a schematic perspective view of a portion of a base plateaccording to one embodiment.

FIG. 6 is a cross-sectional view of a portion of the base plateaccording to one embodiment.

FIG. 7 is a schematic perspective view of one embodiment of the baseplate.

FIG. 8 is a top view of one embodiment of a second sensor element.

FIG. 9 is a cross-sectional view of a portion of the base plateaccording to one embodiment.

FIG. 10 is a schematic overview of embodiments of a system for detectingmoisture propagation in a base plate for an ostomy appliance accordingto a second aspect of the disclosure.

DETAILED DESCRIPTION

In the following Detailed Description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is used withrespect to the orientation of the Figure(s) being described. Becausecomponents of embodiments can be positioned in a number of differentorientations, the directional terminology is used for purposes ofillustration and is in no way limiting. It is to be understood thatother embodiments may be utilized and structural or logical changes maybe made without departing from the scope of the present invention. Thefollowing detailed description, therefore, is not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims.

It is to be understood that the features of the various exemplaryembodiments described herein may be combined with each other, unlessspecifically noted otherwise.

Throughout this disclosure, the words “stoma” and “ostomy” are used todenote a surgically created opening bypassing the intestines or urinarytract system of a person. The words are used interchangeably, and nodifferentiated meaning is intended. The same applies for any words orphrases derived from these, e.g. “stomal”, “ostomies” etc. Also, thesolid and liquid wastes emanating from the stoma may be referred to asboth stomal “output,” “waste(s),” and “fluids” interchangeably. Asubject having undergone ostomy surgery may be referred to as “ostomist”or “ostomate”—moreover, also as “patient” or “user”. However, in somecases “user” may also relate or refer to a health care professional(HCP), such as a surgeon or an ostomy care nurse or others. In thosecases, it will either be explicitly stated, or be implicit from thecontext that the “user” is not the “patient” him- or herself.

In the following, whenever referring to proximal side of a device orpart of a device, the referral is to the skin-facing side, when theostomy appliance is worn by a user. Likewise, whenever referring to thedistal side of a device or part of a device, the referral is to the sidefacing away from the skin, when the ostomy appliance is worn by a user.In other words, the proximal side is the side closest to the user, whenthe appliance is fitted on a user and the distal side is the oppositeside—the side furthest away from the user in use.

The axial direction is defined as the direction of the stoma, when theappliance is worn by a user. Thus, the axial direction is generallyperpendicular to the skin or abdominal surface of the user.

The radial direction is defined as transverse to the axial directionthat is transversely to the direction of the stoma, i.e. “across” thedistal/proximal surface of the base plate. In some sentences, the words“inner” and “outer” may be used. These qualifiers should generally beperceived with respect to the radial direction, such that a reference toan “outer” element means that the element is farther away from a centreportion of the ostomy appliance than an element referenced as “inner”.In addition, “innermost” should be interpreted as the portion of acomponent forming a centre of the component and/or being adjacent to thecentre of the component. In analogy, “outermost” should be interpretedas a portion of a component forming an outer edge or outer contour of acomponent and/or being adjacent to that outer edge or outer contour.

The use of the word “substantially” as a qualifier to certain featuresor effects in this disclosure is intended to simply mean that anydeviations are within tolerances that would normally be expected by theskilled person in the relevant field.

The use of the word “generally” as a qualifier to certain features oreffects in this disclosure is intended to simply mean—for a structuralfeature: that a majority or major portion of such feature exhibits thecharacteristic in question, and—for a functional feature or an effect:that a majority of outcomes involving the characteristic provide theeffect, but that exceptionally outcomes do no provide the effect.

The use of the word “essentially” as a qualifier to certain structuraland functional features or effects in this disclosure is used foremphasizing what is the most important focus of something or fact aboutsomething (i.e. a feature may have or fulfil a variety of effects, butwhen the disclosure discusses one effect as being “essentially”provided, this is the focus and the most important effect in relation tothe disclosure).

Embodiments of the disclosure provides a base plate for an ostomyappliance which facilitates reliable determination of the nature,severity and rapidness of moisture propagation in the adhesive materialprovided for attaching the base plate to the skin surface of a user.Depending on the nature of the pattern of moisture propagation in theadhesive, the base plate of the disclosure helps provide information tothe user about the type of failure, and in turn helps provide anindication to the user of the severity and thus the remaining time framefor replacing the appliance for a fresh one without experiencing severeleakage. A first moisture propagation pattern can correspond to arapidly evolving adhesive failure, which requires immediate attention toavoid a severe leakage incident, e.g. one requiring change of clothesbecause of soiling from stomal output. Another, different moisturepropagation pattern can correspond to a relatively slow evolving,general weakening of the adhesion capacity of the adhesive material,which informs the user that—while perhaps not imminent—replacement ofthe appliance for a fresh one is required because the appliance isapproaching an “end-of-life” condition. Yet other and/or “intermediate”moisture propagation patterns can be envisioned and determined toindicate other conditions of the layer of adhesive material etc.

The ostomy appliance includes a base plate, such as a monolithic,one-piece base plate, e.g. integrated with a sensor assembly part, or abase plate and a separate sensor assembly part, such as a sensorassembly part to be subsequently applied to a base plate. For example,to allow an arbitrary base plate, such as a conventional base plate, toachieve the features as described herein. Features as described withrespect to the base plate herein may be provided by a sensor assemblypart to be applied to a base plate, e.g. by the user. A sensor assemblypart may be adapted to adhere to an ostomy plate.

A disclosed method of attaching a base plate to a user's stoma and/orskin surrounding the stoma, such as the peristomal skin area, maycomprise attaching a sensor assembly part to a base plate and attachingthe base plate, e.g. together with the attached sensor assembly part, tothe user's stoma and/or skin surrounding the stoma, such as theperistomal skin area. Alternatively, the method of attaching the baseplate to the user's stoma and/or skin surrounding the stoma may compriseattaching the sensor assembly part to the user's stoma and/or skinsurrounding the stoma and attaching the base plate to the user's stomaand/or skin surrounding the stoma above the attached sensor assemblypart.

Thus, in one aspect, the present disclosure relates to a base plateand/or a sensor assembly part for an ostomy appliance, comprising atleast a first layer of an adhesive material adapted for attachment ofthe base plate and/or the sensor assembly part to the skin surface of auser; a backing layer comprising a film material forming a distal and aproximal surface of the backing layer, wherein a stoma-receiving openingextending through the base plate and/or the sensor assembly part isprovided in a center portion of the base plate and/or the sensorassembly part surrounding the stoma-receiving opening. The base plateand/or the sensor assembly part further includes a first sensor elementcomprising at least one sensor pair. The sensor pair comprises a firstsensor and a second sensor. Each of the at least first sensor and thesecond sensor is connected to a control unit interface, such that anelectrical signal can be conducted between a respective sensor and thecontrol unit interface. The first sensor element is provided between thefirst layer of adhesive material and the proximal surface of the backinglayer. Moreover, each of the first sensor and the second sensor of thesensor pair comprises a conductor electrode and a ground electrode.Also, the second sensor of the sensor pair is located at a greaterradial distance from the stoma-receiving opening than the first sensorof the sensor pair.

In embodiments, the center portion of the base plate and/or the sensorassembly part is immediately adjacent to and surrounding thestoma-receiving opening of the base plate and/or the sensor assemblypart. In embodiments, the layer of adhesive material can comprise morethan one kind of adhesive material (i.e. “a composition” of adhesivematerials).

In embodiments, the conductor electrode and the ground electrode of eachof the first sensor and the second sensor form a pair of at leastpartially co-extending electrodes. Thereby, the pair of electrodes areprovided next to each other and follow each other over at least some oftheir extent in the first sensor element.

In embodiments, the at least first sensor is adapted as a detectionsensor and configured to detect moisture propagation in the centerportion of the base plate and/or the sensor assembly part. The secondsensor is adapted as a reference sensor configured to detect moisturepropagation in an outlying portion of the base plate and/or the sensorassembly part. The outlying portion is a different portion of the baseplate and/or the sensor assembly part than the center portion. Theoutlying portion and the center portion combine to form the entireextent of the base plate and/or the sensor assembly part. The outlyingportion surrounds the center portion of the base plate and/or the sensorassembly part. In embodiments, the outlying portion is providedannularly around the center portion of the base plate and/or the sensorassembly part.

In embodiments, each of the first and the second sensor includes adetecting portion provided around the stoma-receiving opening and anextension portion extending from the detecting portion of each sensor tothe control unit interface.

In embodiments, in the extension portion, each electrode comprises aninsulating element covering at least a portion of its exposed surface.More portions of an electrode can be covered by insulating elementsdepending on the specific configuration of the electrodes in the firstsensor element.

In embodiments, the first sensor is a radially innermost detectionsensor, and the reference sensor is a radially outermost referencesensor.

The control unit interface is configured for connection to a controlunit. The control unit is a separate unit configured to combine/couplewith the base plate and/or the sensor assembly part of the first aspectof the disclosure. The control unit is adapted to measure or detect anddetermine the meaning of changes in the input received from a firstsensor and from a second sensor. If/when a significant change occurs,this can for example signal a rapid or sudden increase in the quantityof moisture (incl. in liquid form) present at a detection sensor. Incase the reference sensor does not simultaneously detect a similarsignal as was detected by the detection sensor, it signifies that theincrease in moisture level is not also present at the location of thereference sensor. The determination by the control unit of this moisturepropagation pattern is considered unusual and likely represents abeginning leakage. However, the determined pattern also indicates thatthe increase in moisture level (e.g. leakage) has not progressed as farfrom the stoma-receiving opening as to reach the location of thereference sensor. The user is thereby provided with an “early” warning,allowing him/her enough time to replace the ostomy appliance (or takeother measures) and avoid a severe leakage incident. The control unit isfurther described below in relation to the second aspect of thedisclosure.

According to the present disclosure, the “warning time”, i.e. the amountof time available for the user to react to a determined moisturepropagation pattern can be adapted by controlling different factorsand/or parameters. These can include, but are not limited to,controlling; how far from the stoma-receiving opening of the base plateand/or the sensor assembly part a detection sensor is located; applyingmore than one detection sensor at different distances from thestoma-receiving opening; determining changes in measurements between twoor more detection sensors, and by providing a variety of differentalgorithms for use by the control unit, which can provide determinationoptions applicable to more specific moisture propagation patterns.

Experience shows that beginning leakage or the presence of any unusualpropagation of moisture generally occurs starting from the stoma. Thus,an initial attack of propagating moisture practically always takes placeat an innermost edge or rim portion of the base plate at thestoma-receiving opening. However, the moisture can continue itspropagation from the edge or rim portion in any or all radial directionsof the base plate. The moisture propagation can be much more pronouncedin some radial direction(s) than in other radial directions.

In the context of the present disclosure, it is envisioned that changesin a parameter, e.g. changes in the resistance measured at a detectionsensor and/or in the resistance measured at the reference sensor, occurwhen an amount of moisture emerges on the skin surface of the useraround the stoma and propagates into the adhesive material of the baseplate and/or the sensor assembly part. A quantity of emerged moisture onthe skin surface in effect provides an electric conductor, such that themoisture creates a conductive path between the conductor electrode andthe ground electrode. When this happens, the resistance output of thesensor changes, in some situations significantly. If an amount ofmoisture has emerged and propagated into the adhesive material of thebase plate and/or the sensor assembly part and into contact with adetection sensor but not with the reference sensor, the resistancemeasured at each of the sensors will be significantly dissimilar.

In embodiments, the at least first detection sensor is provided in an atleast partly annular configuration around the stoma-receiving opening.Thus, the detection sensor can be provided such that the detectingportion surrounds the stoma-receiving opening, generally in a circleform or circular manner, however without the electrode pair completelyforming a full 360° circle. Instead, in embodiments, the partly annularconfiguration should be interpreted such that an annularly configureddetection sensor includes a relatively small portion where it is “open”.In embodiments, the extension portion extends from the detecting portionof the sensor at or adjacent the “open” portion of the detection sensor.These embodiments provide for a reliable and intuitive construction ofthe first sensor element and facilitates its manufacture as describedotherwhere in this disclosure.

In embodiments, the pair of at least partially co-extending electrodesof each sensor is configured at least partly annularly around thestoma-receiving opening of the base plate and/or the sensor assemblypart. Thereby, the conductor electrode and the ground electrode of asensor both extend generally around the stoma-receiving opening of thebase plate and/or the sensor assembly part, but may also form an “open”portion as described for the first detection sensor.

In embodiments, the conductor electrode and the ground electrode eachare provided as line electrodes. The term “line electrode” should beinterpreted as an electrode of a continuous extent. In one embodiment,the extent in one direction of the electrode is at least five times theextent of the electrode in a direction substantially perpendicular tothe first direction, e.g. in one interpretation the electrode is fivetimes or more longer than it is wide. In embodiments, the conductorelectrode and the ground electrode are provided next to each other in acontinuous manner at least in the detecting portion of each sensor. Inone embodiment, the conductor electrode and the ground electrode areprovided such as to maintain a constant distance between them, at leastin the detecting portion of each sensor. In embodiments, the conductorelectrode and the ground electrode are provided parallel to each other,at least in the detecting portion of each sensor. In someinterpretations, the electrodes can be considered similar to conductivewires or to traces/tracks of an electronic circuit, e.g. such as thoseon a printed circuit board. Such embodiments provide for the electrodesto provide for easy and continuous comparability of the measuredparameter. Moreover, variation of the distance between the conductorelectrode and the ground electrode also provides an option forcontrolling the sensitivity of detecting potential leakage of the baseplate and/or the sensor assembly part.

In embodiments, the at least first detection sensor is located at thecenter portion of the base plate and/or the sensor assembly part. Inembodiments, the at least first detection sensor is adapted to coincidewith the center portion of the base plate and/or the sensor assemblypart, whereby the first detection sensor extends over a major portion ofthe area or zone of the base plate and/or the sensor assembly partdefining the center portion. In embodiments, the center portion of thebase plate and/or the sensor assembly part is defined as a portion ofthe base plate and/or the sensor assembly part from a rim of thestoma-receiving opening and up to (and incl.) a radial distance of up to50 mm therefrom, such as 45 mm therefrom, such as 40 mm therefrom, suchas 35 mm therefrom, such as 30 mm therefrom, such as 25 mm therefrom,such as 20 mm therefrom. In embodiments, a diameter of thestoma-receiving opening is adaptable to between 20-70 mm. Inembodiments, the center portion is alternatively or additionally definedas a portion of the base plate and/or the sensor assembly partcomprising a second skin-friendly adhesive around the stoma-receivingopening. In embodiments, the center portion is alternatively oradditionally defined as a portion of the base plate and/or the sensorassembly part radially inside of a first half of an annular couplingmeans attached to the distal surface of the backing layer. Among otherthings, placing the at least first detection sensor in the centerportion of the base plate and/or the sensor assembly part isadvantageous in that it provides for very early detection of potentialleakage, which is helpful as some users may experience rapid failure ofthe adhesive resulting in a leakage incident, when the stomal output haspropagated underneath the layer of adhesive material. Moreover, placingthe at least first detection sensor in the center portion of the baseplate and/or the sensor assembly part provides a relatively simpleconstruction for manufacture, while additionally being intuitive tousers.

In embodiments, the reference sensor is provided at an outer rim portionof the first sensor element. In embodiments, the outer rim portion ofthe first sensor element is defined at a radially outermost edge portionof the base plate and/or the sensor assembly part. Placing or providingthe reference sensor at the outer rim portion of the first sensorelement is advantageous in that it helps provide a relatively simpleconstruction for manufacture, while additionally being intuitive tousers.

In embodiments, the reference sensor is provided in an essentiallyconcentric manner around the first detection sensor. This provides forpossible early detection of leakage caused by propagating moisture, suchas aggressive visceral fluids exiting from the stoma in any radialdirection in the layer of adhesive of the base plate and/or the sensorassembly part.

In embodiments, the first sensor element further includes one or moreadditional detection sensors, each of the additional detection sensorsbeing provided at different radial distances from the stoma-receivingopening. The one or more additional detection sensors according to theseembodiments help provide for a further increased sensitivity of the baseplate and/or the sensor assembly part in determining if and how moistureis propagating in or under the layer of adhesive of the base plateand/or the sensor assembly part, such as to provide an even more preciseindication of potential or upcoming leakage, or, alternatively, that theostomy appliance is approaching an end-of-life condition.

In embodiments, the first sensor element comprises two or more detectionsensors. Each of the further detection sensor(s) is providedconcentrically around the first detection sensor. Moreover, the firstsensor element is configured such that two detection sensors share oneconcentrically provided ground electrode. Each additional detectionsensor is adaptable to provide an individual indication (input from anindividual location in the layer of adhesive) to the control unit. Forexample: if a first, radially innermost detection sensor indicates asudden abrupt propagation of moisture at its location and is followed bya similar indication from a second detection sensor, located radiallyfarther away from the stoma-receiving opening, the ensuing assumption isthat this moisture propagation pattern is not related to or caused by asimple, continuous uptake of moisture (incl. sweat) from the skin, butindeed very likely to an unusual propagation of stomal output underneaththe adhesive of the base plate and/or the sensor assembly part.

In embodiments, one function of the ground electrode is basically toprovide a return path for an electric current applied via the conductorelectrode, such that a closed loop electric circuit is established.Thus, in embodiments, one (one and only one) ground electrode is adaptedto form the ground electrode of the pair of electrodes of a firstdetection sensor, and to further form the ground electrode of the pairof electrodes of a second (different/additional) detection sensor. Thisis particularly, but not exclusively, advantageous in embodimentswherein the at least two detection sensors are provided concentricallyin relation to each other. In other words, the same (single) groundelectrode can be configured as the ground electrode of the electrodepair of two neighboring and/or adjacent detection sensors. As the groundelectrode functions to establish a closed loop circuit, one singleground electrode can be used by more than one detection sensor (i.e. be“paired” with more than one conductor electrode).

By sharing a ground electrode, i.e. adapting it to function with theconductor electrode of two different, neighboring detection sensors,space is saved allowing the first sensor element to include a relativelyhigher number of detection sensors. Moreover, the construction of thefirst sensor element for manufacture is thereby less complex, easingsize and tolerance requirements, and it is less costly to produce.

In embodiments, knowing the distance between each of a plurality ofindividual detection sensors can additionally help provide an indicationof the pace of the moisture propagation, which in turn can helpdetermine the nature and severity of the moisture propagation. Thus, inembodiments the distance between a first and a second detection sensoris predetermined at manufacture. In embodiments, the distance between afirst and a second sensor is substantially identical to the distancebetween the second sensor and a third sensor and so forth. In otherembodiments, the distance between the first sensor and the second sensor(and/or any further detection sensors) varies. In one embodiment, thedistance between any two detection sensors increases linearly such thatthe distance is greatest between sensors which are closer to an outerrim portion of the first sensor element than to the stoma-receivingopening of the base plate. In addition, the pace of moisture propagationcan further be correlated with empirical data to help make thedetermination.

In embodiments, the extension portion comprises a linear, common groundelectrode which is connected to a ground electrode of each detectionsensor, and optionally further connected to the ground electrode of thereference sensor. The extension portion extends from the detectingportion of each sensor to the control unit interface. The extensionportion provides a conductive path from the electrode pairs of eachsensor to the control unit interface, such that an electrical signal canbe conducted from a respective sensor to the control unit interface. Inembodiments, the conductor electrode of the one or more detectionsensors extends continuously from the detecting portion to the controlunit interface. By “continuously”, it is to be understood that theelectrode does not include any interrupted portions or sections.Additionally or alternatively, “continuously” can be interpreted suchthat even an electrode of a considerable, relative dimension in onedirection is formed to be integral throughout its extent, such thatelectric current can be conducted reliably and sustainably throughoutthe electrode's dimensional extent.

In embodiments, wherein the base plate and/or the sensor assembly partcomprises more than one detection sensor, the conductor electrode ofeach detection sensor extends individually and continuously to thecontrol unit interface. Similarly, in embodiments, the conductorelectrode of the reference sensor extends individually and continuouslyfrom the detecting portion to the control unit interface. Conversely, inembodiments, the ground electrode of the one or more detection sensorsand/or the reference sensor is configured as a linear, common (onesingle) ground electrode extending in the extension portion. In otherwords, in such embodiments the portion of the ground electrode of eachof the sensors in the extension portion forms a single conductive lineor track. The linear, common ground electrode formed by the singleconductive line or track is further connected to the ground electrode ofeach sensor by a connection portion of electrode track. In embodiments,the linear, common ground electrode comprises a plurality (two or more)of connection portions corresponding to the number of detection sensorsplus the reference sensor. In embodiments, the linear, common electrodeand the plurality of connection portions combine to form a tree-likestructure, with the linear, common electrode forming the “tree trunk”and the plurality of connection portions forming branches extending fromthe trunk. Thus, in embodiments, the linear, common ground electrode inthe extension portion is connected to the ground electrode of eachelectrode pair and is adapted to close the circuit loop for any of thedetection and/or reference sensors. Like above, at least some of thebeneficial effects of these embodiments include that the sensor elementis of a less complex construction, easing size and tolerancerequirements and lowering manufacturing costs.

In embodiments, the first sensor element comprises a layer or a sheetcomponent. In embodiments, the one or more detection sensor(s) and thereference sensor of the first sensor element are printed or etched ontothe layer or sheet component of the first sensor element. Other ways ofconfiguring the first sensor element with the detection sensor(s) and/orthe reference sensor are acceptable, provided these do not affect theirsuitability as components of the base plate of an ostomy appliance. Inembodiments, the layer or sheet component of the first sensor elementcomprises a polyurethane (PU) material and/or an ethylene vinyl acetate(EVA) material. In embodiments, the layer or sheet component of thefirst sensor element comprises an adhesive material for attaching thefirst sensor element to the proximal surface of the backing layer. Inembodiments, the adhesive material is provided as a tie layer on adistal surface of the first sensor element, or on the proximal surfaceof the backing layer. Other ways of attaching the first sensor elementto the proximal surface of the backing layer, such as including welding,are also acceptable provided the attachment or the attaching processdoes not influence the electrodes or any other characteristic of thefirst sensor element.

In embodiments, at least a portion of the layer or sheet component isadapted to be moisture permeable. In one embodiment, the entire layer orsheet component is adapted to be moisture permeable. In embodiments,only a portion of the layer or sheet component is adapted to be moisturepermeable, e.g. a portion corresponding in size and shape to the centerportion of the base plate or a portion corresponding to an outlyingportion of the base plate and/or the sensor assembly part, and/or to anouter rim portion of the first sensor element.

In some implementations, the layer or sheet component of the firstsensor element is made moisture permeable to e.g. provide for the optionof embedding the electrode pairs of each of the sensors in the materialof the layer or sheet component. Thus, in embodiments, the electrodepairs of the sensors are embedded in the layer or sheet component of thefirst sensor element. In one embodiment, the layer or sheet componentcomprises a planar distal surface and a planar proximal surface, andwith each sensor embedded in the layer or sheet component.

In embodiments, any proximally facing portion of an electrode isconfigured to be approximately 1 mm from a proximal surface of the firstlayer of adhesive material prior to the base plate and/or the sensorassembly part being applied to the skin surface.

Embedding the electrodes in the layer or sheet component provides forthe first sensor element of the base plate to be less sensitive to“allowable moisture” e.g. in the form of sweat secreting from the skinsurface of the user over time. Thus, if moisture reaches the electrodesrelatively quickly after the user has applied the base plate and/or thesensor assembly part to the skin surface, this is a strong indication ofan unusual moisture propagation pattern such as sudden and/or rapidacting leakage underneath the adhesive. Thus, in embodiments, applyingthe electrodes in the sensor element approximately 1 mm from theproximal surface of the adhesive material, provides a balancedsensitivity of the first sensor element in regard to being able todistinguish between “allowable moisture” secreted relatively slowly assweat from the skin, and rapidly emerging moisture originating fromstomal output.

Other or additional parameters and factors can be controlled to adaptthe base plate and/or the sensor assembly part to provide for deliveringa customized or specialized indication as a reaction to the differentpatterns of moisture propagation. These include, but not exhaustively,providing embedded electrodes “deeper” or “shallower” in the sensorelement; providing two or more electrodes at different radial distancesfrom the stoma-receiving opening of the base plate and/or the sensorassembly part; providing two or more embedded electrodes at different“depths” in the layer or sheet component of the sensor element;controlling a thickness of the adhesive material covering theelectrodes, e.g. to maintain a constant thickness of the layer ofadhesive material or alternatively to vary the thickness of the layer ofadhesive material across the portion covering the electrodes and/or,such as the center portion and/or the outlying portion of the base plateand/or the sensor assembly part, and by combinations of these parametersand factors.

In embodiments, each electrode of the sensors is provided in one and thesame plane of the layer or sheet component. This provides a relativelysimple structure of the first sensor element, which is advantageous toreduce complexity and manufacturing costs.

In embodiments, the electrodes of the sensors are printed on to one ofthe planar surfaces of the layer or sheet component. In one embodiment,the electrodes are printed on to the planar proximal surface of thelayer or sheet component. Thereby, in some embodiments, the electrodesof the sensors can have direct contact with (are directly exposed to)the adhesive material of the base plate and/or the sensor assembly part.This provides for a direct and undelayedly sensor response when adhesivematerial initially covering the electrodes has deteriorated.Particularly, but not exclusively, such embodiments optimize the firstsensor element for (early) sensoring/detection of a sudden unusualmoisture propagation pattern in the base plate and/or the sensorassembly part, and thus more directed towards “leakage” (rapid emergingmoisture propagation) detection than towards “degradation” (slowemerging moisture propagation) detection.

In embodiments, the conductor electrode and/or the ground electrodecomprise(s) a silver material and/or a carbon black material. Inembodiments, the electrodes comprise one or more inks containing acarbon black material. In one embodiment, carbon black containingelectrodes are printed onto the layer or sheet component of the firstsensor element. In embodiments, a thickness of the electrodes of thefirst sensor element is approximately 20 μm. Alternatively, theelectrodes can be applied to the first sensor element by a laminatingprocess or by a punching process. Alternatively or additionally, theelectrodes can be provided from other solution-based materials, such asorganic semiconductors, inorganic semiconductors, metallic conductors,nanoparticles, nanotubes and others.

In embodiments, a second layer of adhesive material is provided on theproximal surface of the backing layer, and wherein the first sensorelement is provided between the first layer of adhesive material and thesecond layer of adhesive material. In embodiments, the adhesive materialof the second layer of adhesive material is identical to the adhesivematerial of the first layer of adhesive material. In embodiments, theadhesive material of the second layer of adhesive material is differentthan the adhesive material of the first layer of adhesive material. Inembodiments, the second layer of adhesive material is adapted to beparticularly resistant to stomal output. In embodiments, the secondlayer of adhesive material is adapted to be particularly suitable forbeing applied at an outlying portion of the base plate and/or the sensorassembly part, e.g. an adhesive having a high initial tack such as anacrylate-based type adhesive. In embodiments, the second adhesive isconfigured to cover or coincide with the center portion of the baseplate and/or the sensor assembly part. In embodiments comprising both afirst layer of an adhesive material and a second layer of an adhesivematerial, the first layer of adhesive material is advantageously adaptedto be particularly resistant to stomal output, and the second layer ofadhesive material is advantageously adapted to be particularly suitablefor ensuring a strong adhesion to the skin surface.

Alternatively or additionally, in embodiments the first layer ofadhesive material comprises a plurality of through-going openings, suchthat each through-going opening provides access to at least one of theelectrodes of an electrode pair of a detection sensor. Thereby, eachthrough-going opening provides a passageway for moisture to pass throughthe first layer of adhesive material and into contact with the at leastone electrode of the detection sensor. In such implementations, thefirst layer of adhesive has a certain thickness. In embodiments, thethickness of the first layer of adhesive is approximately 1 mm, at leastwhen the base plate and/or the sensor assembly part is initially appliedto the skin surface. The electrodes of the detection sensor are thus notlocated immediately adjacent to or on the skin surface of the user.Instead, the electrodes of the detection sensor can be understood to beelevated in relation to the skin surface. This in turn provides for theelectrodes of the detection sensor to be less prone and/or susceptibleto slowly emerging moisture (sweat) from the skin surface. Thereby, inthese embodiments, the base plate and/or the sensor assembly part isconfigured with particular focus on detecting “direct” leaking oroutflow of stomal output from the stoma. By providing the plurality ofthrough-going openings in the first layer of adhesive material, it isensured that the base plate and/or the sensor assembly part hasincreased sensitivity to such “direct” leaking or outflow. Put simply,the plurality of through-going openings basically make it easy for thestomal output to quickly reach the electrodes of the detection sensor.In embodiments, the same or a similar effect can alternatively oradditionally be achieved by applying a wicking and/or a hydrophilicmaterial layer between the layer of the first adhesive and the firstsensor element.

Particularly, but not exclusively, this is advantageous for directingthe first sensor element to uses of detecting sudden leakages, oradhesive failure, in the immediate peristomal area. By applying aplurality of through-going openings, any rapid-acting or rapid-emergingamount of moisture emanating directly from the stoma can be easily andquickly detected by the first sensor element.

In embodiments, a first group of openings of the plurality ofthrough-going openings is radially offset from a second group ofopenings of the plurality of through-going openings. Thereby, eachthrough-going opening of the first group provides access to theelectrode pair of a first detection sensor, and each through-goingopening of the second group provides access to one of the electrodes ofthe first detection sensor and to one of the electrodes of a seconddetection sensor. This is particularly, but not exclusively,advantageous in that one of the electrodes, particularly a groundelectrode, can be a common shared electrode of first and seconddetection sensors. This reduces the number of necessary electrodes andthus the complexity of the sensor element and manufacturing costs.Moreover, the requirements for receiving and processing data input inthe control unit according to the second aspect of the disclosure can bereduced.

In embodiments, the plurality of through-going openings is distributedin a generally circular configuration around the stoma-receivingopening. In other words, each opening of the plurality of openings islocated as following a pattern of a circular figure. Depending interalia on the desired sensitivity and precision of the first sensorelement, the plurality of openings can be selected accordingly. Inembodiments, the plurality of openings comprises between 2-30 openings.In embodiments, the plurality of openings is even in number. In otherembodiments, the plurality of openings is uneven in number. Theplurality of openings is particularly advantageous when the sensors,particularly the one or more detection sensors are providedconcentrically around the stoma-receiving opening and/or the centerportion of the base plate and/or the sensor assembly part. Inembodiments, the plurality of through-going openings is evenlydistributed around the stoma-receiving opening.

In embodiments without through-going openings in the first layer ofadhesive material, the base plate and/or the sensor assembly part canalso be configured such that the electrodes of a detection sensor arenot located immediately adjacent to, or on the skin surface of the user.Like before, the electrodes of a detection sensor can be understood tobe elevated in relation to the skin surface. In embodiments, thedetection sensor is covered by the adhesive material. In embodiments,the layer of adhesive material is approximately 1 mm thick, at leastwhen the base plate and/or the sensor assembly part is initially appliedto the skin surface. However, because the through-going openings are notpresent, the electrodes of the detection sensor are here less subjectedto rapid emerging moisture outflow from the stoma. Thereby, in theseembodiments, the base plate and/or the sensor assembly part isconfigured with particular focus on detecting “wear” of the adhesivematerial of the base plate and/or the sensor assembly part.

In embodiments, the base plate and/or the sensor assembly part of thefirst aspect of the disclosure further comprises a sacrificial materialprovided on the distal surface of the backing layer. In embodiments, thesacrificial material comprises a neutralizing component. In embodiments,the sacrificial material is provided as a layer located on the distalsurface of the backing layer. The sacrificial material and theneutralizing component are described in more detail below.

In embodiments, the base plate and/or the sensor assembly part furthercomprises a second sensor element provided between the layer ofsacrificial material and the distal surface of the backing layer. Thisis particularly advantageous in that additional security and/orcertainty against leakage occurring is provided. By providing a secondsensor element separate from the first sensor element and locating itbetween the sacrificial material and the distal surface of the backinglayer, the user can be provided with an indication of the status of thesacrificial material. If/when the quantity of sacrificial materialreaches a predetermined minimum value, the second sensor element signalsa change in a measured or determined parameter to the control unit,which in turn can be configured to inform the user that the sacrificialmaterial is used up, or close to being so, thereby indicating thatreplacement of the base plate and/or the ostomy appliance is potentiallyrequired.

In embodiments, the second sensor element comprises one or moredetection sensors each comprising a pair of parallelly extendingelectrodes defining a detecting portion configured to be locatedessentially around the stoma-receiving opening. Each sensor of thesecond sensor element further includes an extension portion adapted toextend from the detecting portion to the control unit interface of thebase plate and/or the sensor assembly part. Other attributes and/orcharacteristics of the first sensor element, such as the choice ofmaterial of the element itself and the material of the electrodes, canbe applied analogously to the second sensor element. In embodiments, thesecond sensor element is provided as a generally annular or ring-shapedcomponent, e.g. provided as a cut-out of a film or foil of EVA or PU. Inembodiments, the second sensor element includes a single (one and onlyone) sensor. Thus, in embodiments, the addition of the second sensorelement can be understood to provide the base plate and/or the sensorassembly part also with an additional “wear indicator”, in the sensethat the layer of sacrificial material is equipped with its “own”dedicated sensor element for detecting when the sacrificial material haseroded away fully, or to a certain pre-determined extent. The latter canbe influenced by a variety of controllable parameters/factors, such asthe nature of the sacrificial material, the “depth” and orientation ofthe electrodes of the second sensor element and/or the radial distanceby which the sensor(s) of the second sensor element is separated fromthe stoma-receiving opening of the base plate and/or the sensor assemblypart. Particularly, with regard to the latter factor, the greater theradial distance, the longer it assumedly takes before stomal output haseroded away the sacrificial material.

In embodiments, the electrodes of the one or more detection sensors ofthe second sensor element are adapted to face or point towards thedistal surface of the backing layer. This construction provides for an“output trap” if/when the sacrificial material has eroded away.

In embodiments, one or more of the backing layer, the first sensorelement and the second sensor element describes a generally circularfigure, however further comprising a flap portion extending radiallyaway from an outermost rim portion of the circular figure, the flapportion in at least some embodiments configured to coincide with theextension portion of the sensors. The flap portion can be interpreted asa cantilevered portion of the first and/or second sensor element,extending off an outermost edge or rim of the sensor element.Particularly, but not exclusively, the flap portion is adapted toprovide or function as a base for the control unit interface distancedfrom any rapid-emerging moisture or leakage from the stoma, and easilyaccessible. Moreover, the flap portion provides a suitable location forconnection of a control unit to the base plate and/or the sensorassembly part in a system according to the second aspect of thedisclosure.

In embodiments, the backing layer comprises a woven or a non-wovenmaterial. In one embodiment, the backing layer is a thermoplasticpolymer film. In one embodiments, the backing layer comprises an elasticmaterial. In one embodiment, the backing layer is suitably capable oftransmitting moisture and may e.g. be made from polymers such aspolyolefin types e.g. PE, PP or polybutylene, polyamide such as nylon,polyurethane, polyvinyl acetate, polyvinyl chloride, fluorinatedpolyvinyl compound, polyvinylidene chloride, polyvinyl alcohol, ethylenevinyl acetate, cellulose acetate or other thermoplastic polysaccharides,polyether block amides such as PEBAX® from Arkema, France, blockcopolymers like styrene-isoprene-styrene block copolymers or ethyleneacrylate block copolymers, polyesters such as polyethylene terephthalate(PET) or derivates thereof and any laminates from such polymers. Inother embodiments, the backing layer comprises a thin foam layer madefrom e.g. polyurethane, polyethylene or polyvinyl acetate.

In embodiments, the base plate further comprises a first half of acoupling means configured for releasable coupling with a second half ofa coupling means on a stomal waste collecting bag, the first half of thecoupling means being attached to the distal surface of the backinglayer.

In embodiments, the first coupling half is a flange adapted to provide asurface for attaching the second coupling half in the form of anadhesive flange provided on a stomal output collecting bag. Inembodiments, the first half of the coupling is configured as a flexible,planar annular flange optionally comprising an adhesive. The firstcoupling half is adapted to couple with the second coupling halfprovided around an inlet opening of a stomal output collecting bag bymeans of an adhesive. The adhesive coupling may provide a releasable ora permanent adhesive coupling engagement between the base plate and thecollecting bag.

In embodiments, the first coupling half is an annular ring comprising anupstanding flange, protruding perpendicularly from the distal surface ofthe base plate, for attaching the second coupling half in the form of acoupling ring provided on the stomal output collecting bag. In oneembodiment, the annular ring is attached to the distal surface of thebacking layer. In embodiments, the first coupling half is attached tothe distal surface of the backing layer by an adhesive or by welding,but other ways of attaching are acceptable. In embodiments, the firstcoupling half is attached to a distal surface of the base plate at alocation radially farther away from the stoma-receiving opening than anylocation of one or more detection sensors of the sensor element.

In embodiments, the first half of the coupling means is provided on aseparate connection component. In embodiments, the separate component isadapted to further include a housing for the control unit interface. Inembodiments, the separate connection component is an injection-mouldedcomponent. In embodiments, the connection component further includes aplurality of openings adapted for attachment of an ostomy belt. Inembodiments, the housing for the control unit interface is adapted toinclude means for repeated connections and disconnections of the controlunit from the control unit interface. In embodiments, the housing forthe control unit interface is further adapted to receive one or moreelectrode ends of the electrodes of the first and/or second sensorelements. In embodiments, the housing for the control unit provides anelectrode terminal for all the electrodes of the first and/or secondsensor elements.

In embodiments, the base plate further comprises a first half of acoupling means configured for releasable coupling with a second half ofa coupling means on a stomal waste collecting bag. The first half of thecoupling means is attached to the distal surface of the backing layer,such that a radial extent of sacrificial material provided on the distalsurface of the backing layer is delimited by the first half of thecoupling means. The first half of the coupling means can be understoodto combine with an edge of the stoma-receiving opening for defining anarea of the base plate provided with the sacrificial material. Inembodiments, this area or zone provides or is coincident with the centerportion of the base plate. Thereby, an outermost rim of the sacrificialmaterial is sealingly engaged with an innermost rim portion of the firsthalf of the coupling means. Thus, in embodiments the radial extent ofthe sacrificial material does not go, or extend, beyond an innermostportion, such as an internal perimeter of the first half of the couplingmeans.

In embodiments, a zone or area covered by the sacrificial materialcoincides with the center portion of the base plate and/or the sensorassembly part. In embodiments, wherein the base plate and/or the sensorassembly part comprises a second sensor element as described herein, thesacrificial material coincides with the center portion of the base plateand/or the sensor assembly part and a single detection sensor of thesensor element locates at a radial distance from the stoma-receivingopening being such that the sensor abuts or is immediately adjacent aninnermost portion of the first half of the coupling means, such as at aninner perimeter of an annular coupling ring.

In embodiments, the first sensor element is formed from a stretchablematerial. Also, each of the electrodes of the first sensor element areconfigured to be stretchable and adapted to conform to any movements ofthe stretchable material of the first sensor element. In thisdisclosure, “stretchable” should be interpreted as a material capable ofbeing easily stretched and resuming former size or shape.

In embodiments, the sacrificial material comprises an adhesive. In otherembodiments, the sacrificial material comprises a powder. In otherembodiments, the sacrificial material comprises a liquid. In otherembodiments, the sacrificial material comprises a gel. In otherembodiments, the sacrificial material comprises a plurality of pellets.In yet other embodiments, the sacrificial material comprises acombination of any one or more of an adhesive, a powder, a liquid, a geland/or a plurality of pellets. These options each provides one or moredifferent advantages including, but not limited to, manipulability,shelf life, suitability for different kinds of stomal output (colostomyoutput tends to be much more solid than ileo- and urostomy output),processing characteristics and others.

By “neutralizing component” herein is meant a substance capable ofneutralizing or at least minimizing the level of skin- oradhesive-aggressiveness of the stomal output. In embodiments, whereinthe sacrificial material comprises a neutralizing component, theneutralizing component can comprise a clay, such as organophilic clay,for example bentonite or synthetic clay such as laponite. Inembodiments, the neutralizing component may be potato-derived inhibitorsor protease inhibitors. Examples of potato-derived inhibitors such aspotato protein are disclosed in EP 1 736 136.

In embodiments, the sacrificial material is in the form of a matrixcomposition with a neutralizing component incorporated. The neutralizingcomponent can be dissolved in the matrix composition or it can bedispersed as particles in the matrix. In embodiments, the matrix can bein the form of coated neutralizing component particles.

In embodiments, the matrix is designed to release neutralizing componentto the environment when the matrix is exposed to certain conditions.Such conditions may for example be in the presence of output from thestoma or in the presence of moisture (incl. sweat) as such.

In embodiments, the matrix is in the form of a gel, foam, film layer orpaper or a coating.

In embodiments, a suitable example of a matrix composition could be anadhesive comprising 50% w/w polyisobutylene (PIB) and 25% w/w CMC and25% w/w pectin.

In embodiments, a matrix composition in the form of a water-soluble filmcan be a PVOH based thermoplastic film, such as a Monosol® 7031 filmfrom kurakay WS Film Division™, Portage, Ind., United States.

In embodiments, the matrix is soluble in water or a component of thestomal output. It may be slowly soluble, by slowly is herein meant thatthe matrix layer will not be washed away instantly, but will slowlydissolve during wear time of the wafer.

In embodiments, the matrix can absorb moisture and turn into a gel likematerial when wetted. The gel may be delivered in dry form but swellinto a gel when brought into contact with moisture. The gel may beslowly soluble in water or in a component of the output or it may beinsoluble, but able to release the neutralizing component when exposedto the output or moisture.

In embodiments, the matrix comprises polysaccharides and/orhydrocolloids. The polysaccharides or hydrocolloids may dissolve orhydrate when exposed to stomal output, thereby releasing theneutralizing component.

In embodiments, the matrix comprises protein. In embodiments, the matrixcomprises gelatine.

In embodiments, the matrix is a material capable of forming a gel whenwetted. Examples of suitable materials for the matrix composition may bepolyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), ethylene vinyl acetate (EVA) based matrix andhydrocolloids such as CMC or gelatine. In embodiments, the matrix issubstantially non-adhesive. By non-adhesive is meant that it is notadhesive, though it may under certain circumstances become slightlysticky.

A second aspect of the disclosure concerns a system for determining andsignaling moisture propagation in an adhesive material layer of a baseplate and/or a sensor assembly part for an ostomy appliance. The systemaccording to the second aspect comprises the base plate and/or thesensor assembly part according to the embodiments of the first aspect ofthis disclosure, and a control unit configured for connection with thecontrol unit interface of the base plate and/or the sensor assemblypart. In embodiments, the control unit is adapted to measure or detect achange. This can include, in one sense, that input received from thefirst sensor changes to be significantly different from input receivedfrom the second sensor. In embodiments, the input received from a sensorresembles or corresponds values for resistance of the material of thebase plate and/or the sensor assembly part measured between theconductor electrode and the ground electrode at each of the first sensorand the second sensor. In some implementations, the resistance of thematerial of the base plate and/or the sensor assembly part between theelectrodes before it is engaged by moisture, is of such magnitude thatan actual measurement or determination is irrelevant. Instead, undersuch conditions, the sensor's detection can be seen as an either/orindication—when no moisture has reached the relevant sensor, theresulting reading is “off”. Conversely, when the relevant sensor isengaged by moisture, the resulting reading is “on” and provided as areal value.

If/when a significant change in measured resistance occurs, particularlymaterializing as an abrupt drop in the resistance of material of thebase plate and/or the sensor assembly part only at the first (detection)sensor, this signals a sudden increase in the quantity of moisture(incl. in liquid form) present in the adhesive material at the firstsensor, but not (yet) in the adhesive material at the second (reference)sensor. The sudden drop in resistance occurs because the suddenlyincreased quantity of moisture creates a direct and much more preferredconductive path for electrical current to run between the electrodes ofthe detection sensor, than through the material of the sensor element.If the reference sensor does not measure a similar abrupt change, itmeans that the increase in moisture level is not also present at thelocation of the reference sensor. The determination by the control unitof this moisture propagation pattern likely represents a beginningleakage. However, the pattern further indicates that the increase inmoisture level (e.g. leakage) has not progressed as far from thestoma-receiving opening as the location of the reference sensor. Theuser is thereby provided with an “early” warning, allowing him/herenough time to replace the ostomy appliance (or take other measures) andavoid a severe leakage incident.

In embodiments, the measured parameter is the electrical resistance(resistivity) of the material of the sensor element between theconductor electrode and the ground electrode of each sensor. Immediatelyafter application of the adhesive of the base plate and/or the sensorassembly part to the skin surface, the detection sensor and thereference sensor each will detect a certain initial value for theresistance. In embodiments, the electrodes of each of the individualsensors are provided with identical distances between them. Thus, inembodiments, the measured resistance between the electrodes of the first(detection) sensor will be generally identical to the measuredresistance between the electrodes of the second (reference) sensor. Asdescribed above, this resistance may of such a magnitude that an actualreading of a value when no moisture is present, is irrelevant.

Over time, the skin surface of the user will secrete moisture. Assumingthat the moisture secreting of the skin will generally be of the samemagnitude at the detection sensor and at the reference sensor, themeasured resistance assumedly decreases generally at the same steadyrate at the location of the detection sensor and at the location of thereference sensor. This is because the adhesive material takes upmoisture at a steady pace over its entire area. However, if suddenly thedetection sensor measures an abrupt drop in the resistance between theconductor electrode and the ground electrode of the detection sensor,then that sudden drop is indicative of a change in the conductivity ofthe material between the electrodes due to a drastic moisture or wetnesspropagation between the electrodes. This detection in turn is likely tobe indicative of the presence of stomal output having entered underneaththe base plate and/or the sensor assembly part and having begun erodingaway adhesive material. Conversely, if the measured resistance at thedetection sensor and at the reference sensor continues to drop at asteady rate, and/or a sudden drop in resistance between the electrodesof the reference sensor is experienced, then this is likely to beindicative of the base plate and/or the sensor assembly part having“wetted steadily up” and reached, or almost reached, an end of lifecondition requiring replacement.

In embodiments, the control unit can be adapted to measure a change inresistance between two or more detection sensors and/or the referencesensor. Other parameters and/or factors than resistance can be measuredto determine changes representing moisture propagation, including, butnot limited to, measuring a change in electrical conductivity.

In embodiments, knowing the distance between each of a plurality ofindividual detection sensors can additionally help provide an indicationof the pace of the moisture propagation, which in turn can helpdetermine the nature and severity of the moisture propagation. Inaddition, the pace of moisture propagation can further be correlatedwith empirical data to help make the determination. In embodiments,analysis of such empirical data forms part of the basis for providingone or more customized algorithms for application in the control unit,such that the control unit is adaptable to distinguish and determinebetween a variety of different moisture propagation patterns in the baseplate and/or the sensor assembly part. Thus, in embodiments, the controlunit is configured to distinguish between different patterns of moisturepropagation in the first and/or second layer of adhesive material of thebase plate and/or the sensor assembly part.

In embodiments, the control unit is configured to categorize analogousor like changes in a measured or determined parameter value between adetection electrode and a reference electrode as a first moisturepropagation pattern in a layer of adhesive material of the base plateand/or the sensor assembly part, and to categorize dissimilar changes inthe measured or determined parameter value at the detection electrodeand the reference electrode as a second, different moisture propagationpattern in the layer of adhesive material.

In embodiments, the control unit is further adapted to treat the firstmoisture propagation pattern as a normal moisture propagation pattern,and to treat the second, different moisture propagation pattern as anunusual moisture propagation pattern.

In embodiments, the control unit is configured to give off a signal inresponse to some, but not all, determined patterns of moisturepropagation in the first and/or second layer of adhesive material.Particularly, but not exclusively, in embodiments, the control isconfigured to give off a signal in response to the detection ordetermination of an unusual moisture propagation pattern. Inembodiments, the control unit is further configured to provide a specialindication signal if an unusual moisture propagation pattern isdetermined. In embodiments, the signal is an alarm signal provideddirectly by the control unit. In embodiments, the alarm signal can beany one or more of an audible, a visible or a tactile signal. Inembodiments, the control unit is configured to give off a data signaland transmit it to another entity, such as a data receiving unit and/ordata storage and/or a data processing system. In embodiments, the systemaccording to the second aspect further includes a data processing systemadapted to receive, collect and store data and provide for theperformance of analyses of the data, and generate an output which formspart of a basis for further optimizing one or more moisture propagationpattern algorithms on an individual user basis, which optimizedalgorithms can be input into the control unit for future improvedprecision of the system.

In embodiments, the control unit is configured to provide a normaloperation signal when a normal moisture propagation pattern isdetermined. The control unit can be configured to give off a continuousaudible or visible signal at all times during detection of normalpatterns. Alternatively, the control unit can be configured to give offa normal operation signal at periodic intervals. In embodiments, thecontrol unit is configured to give off a significantly different audibleor visible signal if a change in measured parameter is detected ordetermined. In embodiments, the control unit can be configured to giveoff a differentiated warning signal depending on and relative to theseverity of the detected moisture propagation pattern (i.a. if a veryrapid response by the user is required, the warning signal can beconfigured to be much more insisting than if more time is available tothe user).

In embodiments, the control unit further comprises an integrated powerunit. In embodiments, the integrated power unit provides for the controlunit to be independent of outside power sources. Moreover, inembodiments, the integrated power unit helps provide for the controlunit to be adapted as a re-useable component or entity that is separablefrom the base plate and/or the sensor assembly part, such that when abase plate and/or a sensor assembly part is replaced, the control unitis simply removed or disconnected from the control unit interface of the“old” base plate and/or the sensor assembly part/appliance andsubsequently connected to the control unit interface of the “new” baseplate and/or the sensor assembly part having been attached to the user'sskin surface. In embodiments, the system further comprises a separatebase unit configured to receive and communicate with the control unit,at least during appliance replacements. In embodiments, the systemcomprises two or more interchangeable control units providing for atleast one control unit being available for connection to the base plateand/or the sensor assembly part at all times.

In embodiments, the integrated power unit comprises a battery or apiezoelectric element. In embodiments, the battery is configured as arechargeable battery. In embodiments, the rechargeable battery isadapted to be recharged when the control unit is connected to theseparate base unit, i.a. during appliance replacement.

In embodiments, the system comprises means for connecting the controlunit to the control unit interface of the base plate, which means is/areadapted for repeated connections and disconnections of the control unitfrom the control unit interface of the base plate. In one embodiment,the means comprise first and second magnetic coupling halves for easyand intuitive coupling of the control unit to the base plate. Otherreliable and intuitive coupling types are acceptable.

In embodiments, the control unit further comprises means for wirelessdata communication with a data receiving unit. In embodiments, the meansfor wireless data communication comprises a Near Field Communication(NFC) unit. Alternatively, a wired connection for the communicationand/or transfer of data can be used.

In embodiments, the system further comprises a separate data receivingunit configured for wireless or wired data communication with thecontrol unit.

In embodiments, the control unit and/or the means for wireless datacommunication is/are configured to communicate relevant processed datato a customized software application provided on a portable electronicdevice. In embodiments, the control unit is configured to send dataand/or a warning signal to an application software (“App”) on the user'sportable electronic device, such as a watch, smart phone or tablet. Inembodiments, the units and components of the system of the second aspectare adapted to communicate via a Bluetooth® connection.

It is further to be understood, that the sensitivity of the system tomoisture including outflowing stomal output fluids and slowly secretingmoisture, such as sweat, from the skin surface, as well as the system'spreferred functionalities, can be adapted to include solutions accordingto one or more or all of the embodiments disclosed herein. Thereby,particular embodiments of the first and second aspects, can be mixedand/or combined to meet different user requirements. One non-limitingexample is to provide a base plate comprising both a first sensorelement particularly directed to detect rapid emerging moisturepropagation (“direct leakage”/outflow of stomal fluid), and a secondsensor element particularly directed to detect the degree of erosion ofa sacrificial material applied to further protect the load carryingadhesive layer of the base plate. Moreover, these features can furtherbe combined with one or more customized algorithms provided in thecontrol unit. Thereby, increased precision in detecting or determining arest-of-life or time-until-replacement of the base plate can beachieved. This is turn helps the user to avoid severe and embarrassingleakage incidents.

In a further aspect, the disclosure relates to the use of the systemaccording to the second aspect for determining and signaling moisturepropagation in a material layer of a base plate for an ostomy applianceaccording to the first aspect. In a further use embodiment, the materiallayer is an adhesive material. In a further use embodiment, the materialis a material optimized to function as a sacrificial material to slowdown erosion of the layer of adhesive material of the base plate, whichcarries the weight of the ostomy appliance and adheres it to the user'sskin surface.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of one embodiment of a baseplate 20 according to the first aspect of the disclosure.

The base plate 20 comprises a backing layer 24 having a distal surface26 and a proximal surface 28. A first sensor element 34 is providedbetween the proximal surface 28 of the backing layer 24 and a firstlayer of adhesive material 22. FIG. 1 further illustrates embodimentswherein a second sensor element 78 is provided between the distalsurface 26 of the backing layer 24 and a connection component 31including a first half 92 of coupling means 94 for attaching acollecting bag to the base plate 20 for collection of body wastematerial. The connection component 31 further includes a housing 33forming an electrode terminal configured to combine with the controlunit interface 39 of the first sensor element 34. In the illustratedembodiment, it is to be understood that the housing 33 aligns with theextension portion 48 of the first sensor element 34 and with theextension portion 88 of the second sensor element 78. FIG. 1 furtherillustrates the stoma-receiving opening 30 of the base plate. Aplurality of ostomy belt connections 35 are visible on the connectorcomponent 31. Moreover, FIG. 1 illustrates a plurality of through-goingopenings 66 provided in the first layer of adhesive material 22. Alsoindicated is the proximal surface 62 of the first layer of adhesivematerial 22. In embodiments, the backing layer 24 is provided with athrough-hole 25 for providing a passageway for the electrodes of thefirst sensor element 34 to engage with the control unit interface 39 atthe electrode terminal in housing 33. In FIG. 1 , the first and secondsensor elements 34, 78 are provided as a layer or sheet component 56,79.

As previously described, some parts of the illustrated base plate 20,may be provided as a separate assembly to be applied to an existing baseplate, e.g. comprising one or more of the components as described, suchas to provide a base plate like the base plate 20 as described. Forexample, a sensor assembly part 700 may be provided, e.g. comprising thefirst layer of adhesive material 22, the first sensor element 34, thebacking layer 24, and the second sensor element 78. It may be envisionedthat the sensor assembly part 700 may be applied to a generic base platesuch that said base plate and the sensor assembly part 700 incombination achieves the advantages as disclosed herein.

FIG. 2 is a top view of one embodiment of the base plate 20 of thedisclosure viewing down on the proximal surface 28 of the backing layer24. In the illustrated embodiment, a first detection sensor 36 and asecond reference sensor 38 are provided. For illustration purposes, thefirst layer 22 of adhesive material (FIG. 1 ) is not shown. Also, thecontrol unit interface 39 is not indicated. Each of the first detectionsensor 36 and the second reference sensor 38 comprises an electrodepair. In the illustrated embodiment, both of the electrode pairscomprise co-extending conductor and ground electrodes. The co-extendingelectrodes are shown to co-extend with only a short radial distancebetween them. A broken circular line BL provided annularly around thestoma-receiving opening 30 is shown for illustration purposes: line BLindicates a border between the center portion 32 and an outlying portion44 of the base plate 20. FIG. 2 illustrates an embodiment wherein afirst detection sensor 36 is provided in the center portion 32 of thebase plate and the second reference sensor 38 is provided in theoutlying portion 44 of the base plate. The second reference sensor 38 islocated at a distance L2 from the stoma-receiving opening 30 which isgreater than the distance L1 by which the first detection electrode isfrom the stoma-receiving opening 30. It is to be understood, that inembodiments, a first half 92 of a coupling means 94 can be located onthe distal surface 26 (the other side away from the viewer) atapproximately a radial distance from the stoma-receiving opening 30corresponding to where the broken circular line BL is indicated. A pulltab 47 of the backing layer 24 is also shown.

FIG. 3 is a top view of one embodiment of the first sensor element 34 ofthe base plate 20 and/or the sensor assembly part. The first sensorelement 34 is provided as a layer or sheet component 56. In theillustrated embodiment, the first sensor element 34 includes threedetection sensors 36, 50, 52 and reference sensor 38. Each of thesensors 36, 38, 50, 52 includes a conductor electrode 40 and a groundelectrode 42. In FIG. 3 , all sensors 36, 38, 50, 52 surround thestoma-receiving opening 30 and the sensors are further concentricallyarranged in relation to each other. FIG. 3 further schematicallyindicates and illustrates a detecting portion 46 of each of the sensors36, 38, 50, 52 (a detecting portion of one sensor is highlighted by abroken line around the sensor) and also illustrates the extensionportion 48 of each of the sensors. The extension portion 48 is alsohighlighted by a triangular shaped broken line resembling a wedge shape.In the illustrated embodiment, each of the conductor electrodes 40 ofthe sensors extends around the stoma-receiving opening 30 and via theextension portion 48 into a control unit interface 39 of the firstsensor element 34. In the embodiment of FIG. 3 , each of the groundelectrodes 42 extend individually in the detecting portion 46 of thesensors, but combine in a linear, common (shared) ground electrode 54 atthe extension portion 48. Also, FIG. 3 shows how the first sensorelement 34 comprises a flap portion 90 “cantilevering” off from an outerrim portion 49 of element 34. In FIG. 3 , the reference sensor 38 isprovided at an outer rim portion 49 of the first sensor element 34.

FIG. 4 is a cross-sectional view of a portion of the base plateaccording to one embodiment. In the embodiment of FIG. 4 , the baseplate comprises a first layer of an adhesive material 22 and a secondlayer of an adhesive material 64. The first sensor element 34 isprovided between the first layer of adhesive material 22 and the secondlayer of adhesive material 64. The electrodes 40, 42 of the detectionsensors are provided on a proximal side of the first sensor element 34,such that the electrodes face or contact the first layer of adhesivematerial 22. FIG. 4 further illustrates a second sensor element 78provided on the distal surface 26 of the backing layer 24. Theelectrodes 82, 84 of the single sensor 80 of the second sensor element78 face or contact the distal surface of the backing layer 24. FIG. 4further illustrates how a layer of a sacrificial material 74 is providedon the distal surface 26 of the backing layer 24. A portion of thesecond sensor element 78 including the single sensor 80 is providedbetween the distal surface 26 of the backing layer 24 and the layer ofsacrificial material 74. The extent of the layer of sacrificial material74 is radially delimited by a first half 92 of a coupling means 94 andby an edge of the stoma-receiving opening (not shown). In theembodiments of FIG. 4 , the first half 92 of the coupling means 94 isprovided on a connection component 31 attached to the distal surface 26of the backing layer 24.

FIG. 5 is a schematic perspective view of a portion of a base plate 20according to one embodiment. In FIG. 5 , the layer of sacrificialmaterial 74 and the second sensor element 78 are not included. Thefigure illustrates the center portion 28 of the base plate 20 radiallydelimited by the first half 92 of the coupling means. Radially beyondthe first half 92 of the coupling means, the outlying portion 44 of thebase plate is shown. The first half 92 of the coupling means is providedon a connection component 31 which is attached to the distal surface 26of the backing layer 24.

FIG. 6 is a cross-sectional view of a portion of the base plateaccording to one embodiment. In FIG. 6 , the base plate 20 is basicallyof similar construction as the embodiment illustrated in FIG. 4 .However, the first layer of adhesive material 22 is provided with aplurality of through-going openings 66. The openings 66 provided apassageway 68 through the first layer of adhesive material 22. Thisembodiment provides for a fast detection of potential adhesive failureand leakage in that the electrodes of a first detection sensor 50 and ofa second detection sensor 52 are directly exposed to any moisture incl.aggressive stomal fluids. The number and location of the through-goingopenings 66 illustrated is only exemplary and can be adapted accordingto requirements. More than one or all of the sensors can be directlyexposed to moisture via passageways 68.

FIG. 7 is a schematic perspective view of one embodiment of the baseplate 20 and/or the sensor assembly part 700. FIG. 7 shows the proximalsurface 62 of the first layer of adhesive material 22 including aplurality of through-going openings 66. FIG. 7 shows a first group ofopenings 67 of the plurality of through-going openings 66 radiallyoffset from a second group of openings 69 of the plurality ofthrough-going openings 66. Each through-going opening of the first group67 provides access to the electrode pair of the first detection sensor50, and each through-going opening of the second group 69 providesaccess to one of the electrodes of the first detection sensor 50 and toone of the electrodes of the second detection sensor 52. Thus, theground electrode of the two detection sensors 50, 52 can be a commonshared electrode of first and second detection sensors 50, 52. Thenumber of electrodes and the complexity of the first sensor element 34is reduced. In FIG. 7 , the plurality of through-going openings 66 isdistributed circularly around the stoma-receiving opening 30. In theembodiment of FIG. 7 , the plurality of openings comprises 24 openings66.

FIG. 8 is a top view of one embodiment of a second sensor element 78having only a single sensor with a pair of co-extending electrodes 82,84.

FIG. 9 is a cross-sectional view of a portion of the base plate 20according to one embodiment. In the embodiment of FIG. 9 , the baseplate 20 only includes one sensor with a pair of co-extending electrodes82, 84 provided in a sensor element 78. The embodiment is directed atbeing able to detect the level of erosion of the layer of sacrificialmaterial 74 and thus in turn provide an indication of the remaining weartime of the base plate 20 before replacement is needed.

FIG. 10 is an overview of embodiments of a system 110 for detectingmoisture propagation in a base plate 20 and/or a sensor assembly part700. The system 110 comprises a base plate 20 and/or a sensor assemblypart 700 including a control unit interface 39 adapted to be connectedto a control unit 112. The control unit 112 includes an integrated powerunit 114. The control unit 112 is releasably connected to the controlunit interface 39 of the base plate and/or the sensor assembly part, andis configured to be a re-useable component. The control unit 112 furtherincludes instruction processing means 115 which are programmable, e.g.to run one or more algorithms. The control unit 112 includes means 122for wireless communication 123 with a data receiving unit 124. The datareceiving unit 124 can be a separate component as shown, or can beintegrated in the control unit 112 or in another separate, externaldevice. The control unit 112 and/or the data receiving unit 114 cancommunicate with a portable electronic device 128 including a softwareapplication 126 for providing input and/or leakage warnings to the user.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of body side members forostomy appliances as discussed herein. Therefore, it is intended thatthis invention be limited only by the claims and the equivalentsthereof.

EMBODIMENTS

Embodiments of the present disclosure are set out in the followingitems:

1. A sensor assembly part for an ostomy appliance, comprising:

-   -   optionally a first layer of an adhesive material comprising one        or more water soluble or water swellable hydrocolloids adapted        for attachment of the sensor assembly part to the skin surface        of a user;    -   optionally a backing layer comprising a film material forming a        distal and a proximal surface of the backing layer;    -   wherein the sensor assembly part is configured for being        provided with a stoma-receiving opening extending through the        sensor assembly part in a center portion of the sensor assembly        part; and    -   a first sensor element comprising at least one sensor pair, the        sensor pair comprising a first sensor and a second sensor, each        of the first sensor and the second sensor connected to a control        unit interface, such that an electrical signal can be conducted        between a respective sensor and the control unit interface;    -   wherein the first sensor element is optionally provided between        the first layer of adhesive material and the proximal surface of        the backing layer;    -   wherein each of the first sensor and the second sensor of the        sensor pair comprises a conductor electrode and a ground        electrode; and    -   wherein the second sensor of the sensor pair is located at a        greater radial distance from the center portion of the sensor        assembly part than the first sensor of the sensor pair.

2. The sensor assembly part of item 1, wherein the conductor electrodeand the ground electrode of each of the first sensor and the secondsensor form a pair of at least partially co-extending electrodes.

3. The sensor assembly part of item 1 or 2, wherein the at least firstsensor is adapted as a detection sensor and configured to detectmoisture propagation in the center portion of the sensor assembly part,and the second sensor is adapted as a reference sensor configured todetect moisture propagation in an outlying portion of the sensorassembly part.

4. The sensor assembly part of any one of items 1-3, wherein each of thefirst and the second sensor comprises:

-   -   a detecting portion provided around the stoma-receiving opening;        and    -   an extension portion extending from the detecting portion of        each sensor to the control unit interface.

5. The sensor assembly part of item 3 or 4, wherein the at least firstdetection sensor is provided in an at least partly annular configurationaround the stoma-receiving opening.

6. The sensor assembly part of item 2, wherein the pair of at leastpartially co-extending electrodes of each sensor is configured at leastpartly annularly around the stoma-receiving opening of the sensorassembly part.

7. The sensor assembly part of any one of items 3-6, wherein the atleast first detection sensor is located at the center portion of thesensor assembly part.

8. The sensor assembly part of any one of items 3-7, wherein thereference sensor is provided at an outer rim portion of the first sensorelement.

9. The sensor assembly part of any one of items 3-8, wherein thereference sensor is provided in an essentially concentric manner aroundthe first detection sensor.

10. The sensor assembly part of any one of items 3-9, wherein the firstsensor element comprises one or more additional detection sensors, eachof the additional detection sensors being provided at different radialdistances from the stoma-receiving opening.

11. The sensor assembly part of any one of items 3-10, wherein the firstsensor element comprises two or more detection sensors, the furtherdetection sensor(s) provided concentrically around the first detectionsensor and configured such that two detection sensors share oneconcentrically provided ground electrode.

12. The sensor assembly part of item 11, wherein the at least twodetection sensors are provided concentrically in relation to each other.

13. The sensor assembly part of any one of items 4-12, wherein theextension portion comprises a linear, common ground electrode, thelinear, common ground electrode connected to a ground electrode of eachdetection sensor and optionally further connected to the groundelectrode of the reference sensor.

14. The sensor assembly part of item 1, wherein the first sensor elementcomprises a layer or sheet component.

15. The sensor assembly part of item 14, wherein at least a portion ofthe layer or sheet component is adapted to be moisture permeable.

16. The sensor assembly part of item 14 or 15, wherein the layer orsheet component comprises a planar distal surface and a planar proximalsurface, and wherein each sensor is embedded in the layer or sheetcomponent.

17. The sensor assembly part of any one of the preceding items, whereinany proximally facing portion of an electrode is configured to beapproximately 1 mm from a proximal surface of the first layer ofadhesive material prior to the sensor assembly part being applied to theskin surface.

18. The sensor assembly part of any one of items 14-17, wherein eachelectrode is provided in one and the same plane of the layer or sheetcomponent.

19. The sensor assembly part of any one of items 1-18, wherein a secondlayer of adhesive material is provided on the proximal surface of thebacking layer, and wherein the first sensor element is provided betweenthe first layer of adhesive material and the second layer of adhesivematerial.

20. The sensor assembly part of any one of items 3-19, wherein the firstlayer of adhesive material comprises a plurality of through-goingopenings, such that each through-going opening provides access to atleast one of the electrodes of an electrode pair of a detection sensorby providing a passageway for moisture to pass through the first layerof adhesive material and into contact with the at least one electrode ofthe detection sensor.

21. The sensor assembly part of any one of items 10-20, wherein a firstgroup of openings of the plurality of through-going openings is radiallyoffset from a second group of openings of the plurality of through-goingopenings, such that each through-going opening of the first groupprovides access to the electrode pair of a first detection sensor, andsuch that each through-going opening of the second group provides accessto one of the electrodes of the first detection sensor and to one of theelectrodes of a second detection sensor.

22. The sensor assembly part of item 20 or 21, wherein the plurality ofthrough-going openings is distributed in a generally circularconfiguration around the stoma-receiving opening.

23. The sensor assembly part of any one of items 20-22, wherein theplurality of through-going openings is evenly distributed around thestoma-receiving opening.

24. The sensor assembly part of item 1, further comprising a sacrificialmaterial provided on the distal surface of the backing layer.

25. The sensor assembly part of item 24, wherein the sacrificialmaterial comprises a neutralizing component.

26. The sensor assembly part of item 24 or 25, further comprising asecond sensor element provided between the layer of sacrificial materialand the distal surface of the backing layer.

27. The sensor assembly part of item 26, wherein the second sensorelement comprises one or more sensors each comprising a pair ofparallelly extending electrodes defining a detecting portion configuredto be located essentially around the stoma-receiving opening, and anextension portion extending from the detecting portion to the controlunit interface.

28. The sensor assembly part of item 4, wherein one or more of thebacking layer, the first and the second sensor element describes agenerally circular figure, and further comprises a flap portionextending radially away from an outermost rim portion of the circularfigure.

29. The sensor assembly part of any one of items 4-28, wherein each ofthe conductor electrodes of each of the pair of electrodes is configuredto individually extend through the extension portion from the detectingportion of a respective sensor to the control unit interface, andwherein the ground electrodes of each of the pair of electrodes areconfigured to combine into a single, common ground electrode, whichextends through the extension portion along the individual conductorelectrodes from the detecting portion to the control unit interface.

30. A system for determining and signaling moisture propagation in anadhesive material layer of a base plate and/or a sensor assembly partfor an ostomy appliance, comprising:

-   -   the sensor assembly part according to any one of items 1-29; and    -   a control unit configured for connection with the control unit        interface of the sensor assembly part.

31. The system of item 30, wherein the control unit is configured todistinguish between different patterns of moisture propagation in thefirst and/or second layer of adhesive material of the base plate and/orthe sensor assembly part.

32. The system of item 30 or 31, wherein the control unit is configuredto give off a signal in response to some, but not all, determinedpatterns of moisture propagation in the first and/or second layer ofadhesive material.

33. The system of any one of items 30-32, wherein the control unit is atleast configured to categorize analogous or like changes in a measuredor determined parameter value between a detection electrode and areference electrode as a first moisture propagation pattern in a layerof adhesive material of the base plate and/or the sensor assembly part,and to categorize dissimilar changes in the measured or determinedparameter value at the detection electrode and the reference electrodeas a second, different moisture propagation pattern in the layer ofadhesive material.

34. The system of item 33, wherein the control unit is adapted to treatthe first moisture propagation pattern as a normal moisture propagationpattern, and to treat the second, different moisture propagation patternas an unusual moisture propagation pattern.

35. The system of item 34, wherein the control unit is furtherconfigured to provide a special indication signal if an unusual moisturepropagation pattern is determined.

36. The system of any one of items 33-35, wherein the control unit isconfigured to provide a normal operation signal when a normal moisturepropagation pattern is determined.

37. The system of any one of items 30-36, wherein the control unitfurther comprises an integrated power unit.

38. The system of item 37, wherein the integrated power unit comprises abattery or a piezoelectric element.

39. The system of any one of items 30-38, further comprising means forconnecting the control unit to the control unit interface of the sensorassembly part which means is/are adapted for repeated connections anddisconnections of the control unit from the control unit interface ofthe sensor assembly part.

40. The system of any one of items 30-39, wherein the control unitfurther comprises means for wireless data communication with a datareceiving unit.

41. The system of item 40, wherein the means for wireless datacommunication comprises a Near Field Communication unit.

42. The system of item 40 or 41, further comprising a separate datareceiving unit configured for wireless data communication with thecontrol unit.

43. The system of any one of items 40-42, wherein the control unitand/or the means for wireless data communication is/are configured tocommunicate relevant processed data to a customized software applicationprovided on a portable electronic device.

44. Use of the system according to any one of items 30-43 fordetermining and signaling moisture propagation in a material layer of asensor assembly part for an ostomy appliance according to any one ofitems 1-29.

47. Use of the system according to any one of items 32-45 fordetermining and signaling moisture propagation in an adhesive materiallayer of a sensor assembly part for an ostomy appliance according to anyone of items 1-29.

48. The sensor assembly part of any one of items 1-29, wherein the firstsensor element is formed from a stretchable material, and furtherwherein each of the electrodes of the first sensor element areconfigured to also be stretchable and adapted to conform to anymovements of the stretchable material of the first sensor element.

The invention claimed is:
 1. A base plate for an ostomy appliance, comprising: at least a first layer of an adhesive material adapted for attachment of the base plate to the skin surface of a user; a backing layer comprising a film material forming a distal and a proximal surface of the backing layer; wherein a stoma-receiving opening extending through the base plate is provided in a center portion of the base plate; and a first sensor element comprising at least one sensor pair, the sensor pair comprising a first sensor and a second sensor, each of the first sensor and the second sensor connected to a control unit interface, such that an electrical signal can be conducted between the first sensor and the second sensor and the control unit interface, wherein the first sensor extends at least partly annularly around the stoma-receiving opening; wherein the first sensor and the second sensor are provided between the first layer of adhesive material and the proximal surface of the backing layer; wherein each of the first sensor and the second sensor comprises a conductor electrode and a ground electrode; and wherein the second sensor is located at a greater radial distance from the stoma-receiving opening than the first sensor.
 2. The base plate of claim 1, wherein the conductor electrode and the ground electrode of each of the first sensor and the second sensor form a pair of at least partially co-extending electrodes.
 3. The base plate of claim 1, wherein the first sensor is configured to detect moisture propagation in the center portion of the base plate, and the second sensor is configured to detect moisture propagation in an outlying portion of the base plate.
 4. The base plate of claim 1, wherein each of the first sensor and the second sensor comprises: a detecting portion provided around the stoma-receiving opening; and an extension portion extending from the detecting portion of each sensor to the control unit interface.
 5. The base plate of claim 1, wherein the first sensor and the second sensor extend at least partly annularly around the stoma-receiving opening of the base plate.
 6. The base plate of claim 1, wherein the first sensor is located proximal to the center portion of the base plate.
 7. The base plate of claim 1, wherein the second sensor is provided at an outer rim portion of the base plate.
 8. The base plate of claim 1, wherein the second sensor is provided in an essentially concentric manner around the first sensor.
 9. The base plate of claim 1, further comprising one or more additional detection sensors, each of the additional detection sensors being provided at different radial distances from the stoma-receiving opening.
 10. The base plate of claim 1, further comprising two or more detection sensors, wherein the two or more detection sensors are provided concentrically around the first sensor and configured such that two or more detection sensors share one concentrically provided ground electrode.
 11. The base plate of claim 10, wherein the two or more detection sensors are provided concentrically in relation to each other.
 12. The base plate of claim 4, wherein the extension portion comprises a linear common ground electrode, the linear common ground electrode connected to the ground electrode of the first sensor.
 13. The base plate of claim 1, wherein the first sensor element comprises a layer or sheet component.
 14. The base plate of claim 13, wherein at least a portion of the layer or sheet component is adapted to be moisture permeable.
 15. The base plate of claim 13, wherein the layer or sheet component comprises a planar distal surface and a planar proximal surface, and wherein the first sensor and the second sensor are embedded in the layer or sheet component.
 16. The base plate of claim 13, wherein each electrode is provided in one and the same plane of the layer or sheet component.
 17. The base plate of claim 1, wherein a second layer of adhesive material is provided on the proximal surface of the backing layer, and wherein the first sensor element is provided between the first layer of adhesive material and the second layer of adhesive material.
 18. The base plate of claim 3, wherein the first layer of adhesive material comprises a plurality of through-going openings, such that each through-going opening provides access to at least one of the electrodes of the first sensor by providing a passageway for moisture to pass through the first layer of adhesive material and into contact with at least one electrode of the first sensor.
 19. The base plate of claim 18, wherein a first group of openings of the plurality of through-going openings is radially offset from a second group of openings of the plurality of through-going openings, such that each through-going opening of the first group provides access to the electrode pair of the first sensor, and such that each through-going opening of the second group provides access to one of the electrodes of the first sensor and to one of the electrodes of the second sensor.
 20. The base plate of claim 18, wherein the plurality of through-going openings is distributed in a circular configuration around the stoma-receiving opening.
 21. The base plate of claim 18, wherein the plurality of through-going openings is evenly distributed around the stoma-receiving opening.
 22. The base plate of claim 1, further comprising a sacrificial material provided on the distal surface of the backing layer.
 23. The base plate of claim 22, wherein the sacrificial material comprises a neutralizing component.
 24. The base plate of claim 22, further comprising a second sensor element provided between the sacrificial material and the distal surface of the backing layer.
 25. The base plate of claim 24, wherein the second sensor element comprises one or more sensors each comprising a pair of parallelly extending electrodes defining a detecting portion configured to be located around the stoma-receiving opening, and an extension portion extending from the detecting portion to the control unit interface.
 26. The base plate of claim 4, wherein one or more of the backing layer, the first sensor and the second sensor comprise a circular figure, and further comprises a flap portion extending radially away from an outermost rim portion of the circular figure.
 27. The base plate of claim 1, further comprising a first half of a coupling means configured for releasable coupling with a second half of the coupling means provided on a stomal waste collecting bag, wherein the first half of the coupling means is attached to the distal surface of the backing layer.
 28. The base plate of claim 22, further comprising a first half of a coupling means configured for releasable coupling with a second half of the coupling means provided on a stomal waste collecting bag, wherein the first half of the coupling means is attached to the distal surface of the backing layer, such that a radial extent of the sacrificial material is delimited by the first half of the coupling means, whereby an outermost rim of the sacrificial material is sealingly engaged with an innermost rim portion of the first half of the coupling means.
 29. The base plate of claim 4, wherein each of the conductor electrodes is configured to individually extend through the extension portion from the detecting portion of a respective sensor to the control unit interface, and wherein the ground electrodes are configured to combine into a single, common ground electrode, which extends through the extension portion along the individual conductor electrodes from the detecting portion to the control unit interface.
 30. The base plate of claim 1, wherein the first sensor is formed from a stretchable material.
 31. A base plate for an ostomy appliance, comprising: at least a first layer of an adhesive material adapted for attachment of the base plate to the skin surface of a user; a backing layer comprising a film material forming a distal and a proximal surface of the backing layer; wherein a stoma-receiving opening extending through the base plate is provided in a center portion of the base plate; and a first sensor element comprising at least one sensor pair, the sensor pair comprising a first sensor and a second sensor, each of the first sensor and the second sensor connected to a control unit interface, such that an electrical signal can be conducted between the first sensor and the second sensor and the control unit interface, wherein each of the first sensor and the second sensor comprises: a detecting portion provided around the stoma-receiving opening; and an extension portion extending from the detecting portion of each sensor to the control unit interface; wherein the first sensor and the second sensor are provided between the first layer of adhesive material and the proximal surface of the backing layer; wherein each of the first sensor and the second sensor comprises a conductor electrode and a ground electrode; and wherein the second sensor is located at a greater radial distance from the stoma-receiving opening than the first sensor.
 32. The base plate of claim 31, wherein the conductor electrode and the ground electrode of each of the first sensor and the second sensor form a pair of at least partially co-extending electrodes.
 33. The base plate of claim 31, wherein the first sensor is configured to detect moisture propagation in the center portion of the base plate, and the second sensor is configured to detect moisture propagation in an outlying portion of the base plate.
 34. The base plate of claim 31, wherein the first sensor extends at least partly annularly around the stoma-receiving opening.
 35. The base plate of claim 31, wherein the first sensor and the second sensor extend at least partly annularly around the stoma-receiving opening of the base plate.
 36. The base plate of claim 31, wherein the first sensor is located proximal to the center portion of the base plate.
 37. The base plate of claim 31, wherein the second sensor is provided at an outer rim portion of the base plate.
 38. The base plate of claim 31, wherein the second sensor is provided in an essentially concentric manner around the first sensor.
 39. The base plate of claim 31, further comprising one or more additional detection sensors, each of the additional detection sensors being provided at different radial distances from the stoma-receiving opening.
 40. The base plate of claim 31, further comprising two or more detection sensors, wherein the two or more detection sensors are provided concentrically around the first sensor and configured such that two or more detection sensors share one concentrically provided ground electrode.
 41. The base plate of claim 40, wherein the two or more detection sensors are provided concentrically in relation to each other.
 42. The base plate of claim 31, wherein the first sensor element comprises a layer or sheet component.
 43. The base plate of claim 42, wherein the layer or sheet component comprises a planar distal surface and a planar proximal surface, and wherein the first sensor and the second sensor are embedded in the layer or sheet component.
 44. The base plate of claim 31, wherein a second layer of adhesive material is provided on the proximal surface of the backing layer, and wherein the first sensor element is provided between the first layer of adhesive material and the second layer of adhesive material.
 45. The base plate of claim 31, further comprising a first half of a coupling means configured for releasable coupling with a second half of the coupling means provided on a stomal waste collecting bag, wherein the first half of the coupling means is attached to the distal surface of the backing layer. 